Jimmy Carter, the miracle worker of 1976, is now marked by critics as the political incompetent of 1977 whose compulsive industriousness has produced a swirl of confusing objectives and made him an easier prey for the vultures in Washington's power centers.

That a crisis now exists cannot be denied. The hope of Carter insiders that the President's popularity would survive in the countryside while his status fell in Washington was shattered by the NBC poll putting his approval rating at 46 per cent. What makes this descent alarmingly different from past presidential crises is that it comes from no war, no economic collapse and no major scandal.

Rather, its source is deep inside the methods and procedures of the Carter presidency. Although the President's popularity will surely rally, he is liable to stay in trouble so long as he conducts his office as he does now. Thus, the most distressing fact in Washington today is that there is no signal yet pointing to any significant changes in the why Jimmy Carter functions as President.

Although many Democrats blame Carter's problems on the profusion of leftist appointees pushing policies not compatible with his own, the criticism comes equally from left and right. Indeed, part of his troubles may derive from a deficit, not a surplus, of ideology. Not linked to a philosophy other than an obsessive work ethic, the President has forged ahead with overambitious programs, both domestic and international, many parts of which relate to no overall theme.

Voters expected a President bringing calm and stability. Instead, confides one middle-level administration official, "they got a Lyndon Johnson overachiever" just as the presidency was entering a dangerously weakened state induced by Vietnam and Watergate. Carter seeks to be a strong President in the Rooseveltian tradition at a time when the spirit of Congress makes that goal unreachable.

The inevitable defeats suffered in the collision between a massive program and an independent Congress with the bit in its teeth are compounded by the fact that Carter not only is an outsider but came here boasting about it. Lacking real friends in Congress intimately tied to his fortunes, the President was set upon by congressmen acting like vultures sniffing blood from 1600 Pennsylvania Ave.

There are also vultures in his own administration. No recent administration has evidenced less personal loyalty to the President within the departments. Officials at the assistant secretary level, picked by heads of departments in Carter's "Cabinet government," owe their loyalty to the Secretary rather than the President and show no hesitancy about criticizing the President. Lobbying on Capitol Hill, usually a source of White House power, is also diffused with the departments.

In this situation, the President himself - whose political assessments on the road to the White House seldom have been matched in shrewdness - might be expected to assess the situation and change it. Some senior aides believe the prodigious output of domestic and foreign initiatives must be slowed.

But like the sorcerer's apprentice, Carter is too busy to stop the process. A few insiders say his schedule is too fully booked to think seriously about his presidency. Aides proudly point to his appetite for official reading. He has devoted 26 full hours to studying the defense budgert, and more such time is being set aside. He spend much of last week going over 200 pages packed with tax-reform data.

Such totoal immersion would be unimaginable for statesmen such as Otto von Bismarck, Winston Churchill or Charles de Gaulle. "Jimmy sees things that any assistant secretary shouldn't see," one administration official told us. Carter is so deep in details that he seems compelled to push forward, further overloading his circuits.

The answer by many friends is to broaden his staff - "to get some aides in there with a little gray in their hair," in the words of one Cabinet member. Yet it may be unrealistic to believe that newly recruited aides could succeed where old ones have failed in changing what very well may be Carter's set style.

The hard reality is that both the overambitious legislative program and the work habits are pure Jimmy Carter. The blunt assessment of one administration official - "he's not a statesman, he's an engineer" - may be too harsh, but it points to the problem.

Some of Carter's supporters outside the administration believe his first imperative is to slow the made pace and offer voters the impression of calm and orderliness they had expected from him. Instead, he has scheduled frenetic barnstorming, starting coast-to-coast on Oct. 21 and then hitting four continents. Considering its unique nature, the Carter crisis may well be exacerbated by these standard efforts to revive the President's popularity.